FNG question

[Sleek-Jet]

I just purchased my first jet boat, an 18 foot '73 Sleekcraft. It had a 455 Olds (but I canibalized it for another, shall we say...more street bound project) coupled to a Jacuzzi jet, though I am not sure of the model, and a place diverter. I am going to start a restoration on the boat this fall; interior, new power plant, and possibly the floor, the jury is still out on that though. (I know, why not leave the engine in the boat and use it? Well about the only way a boat is going to get wet around here this summer is if I "mark my territory", yes it's that dry!)
My first question is, how hard is it to change engine makes? I would like to build a BB Chevy using a World casting block and drop it in the boat. I took the Olds out last weekend, and it looks like all I have to do is move the mounting brakets forward or aft to fit the motor, then bolt them to the stringer. Is this correct, or am I missing some vital step?
[This message has been edited by Sleek-Jet (edited May 22, 2002).]

[beached1]

Only if your pump is a 12WJ will you be able to use a place diverter, or any diverter like it. Also, if it is a WJ and you are going to install a place, you need to have the nozzle bored out of your bowl. In a place div, the nozzle of part of the diverter because that's how all the other mixed flow makes are setup. Therefore, you would have 2 nozzles in line if you have a Jacuzzi. If you have access to a descent sized lathe you can do this yourself. I chucked mine up and opend it to the vanes. I left about a 1/2" lip so I could still use the stock O ring seal. According to MPD, this is all that needed. I however didn't like the uneven transition from the bowl to the palce div adapter. I made a stuffer from billet that filled this void. Here are some pics.
http://www.beached1.homestead.com/files/Pump2.jpg
Oops. Sorry, I thought I had a url for my billet stuffer. If I get some time later I'll post it.
Hope this helps.

[Sleek-Jet]

Ok, there is a diverter already on the boat, so I guess that makes the pump a WJ. I will not see the boat till this weekend (it's over at a friends shop), but when I get a chance, I'll look at the set up on the diverter.
Thanks for the help.

[Sleek-Jet]

Whoops, hit the button to often I guess!
(or am I just trying to bump my number of posts up?)
[This message has been edited by Sleek-Jet (edited May 23, 2002).]

[superdave013]

I would think that swapping out to a BBC would not be hard at all. Of cource you will need diferent exhaust manifolds but they will be easy to find. If you want to use the old style logs I see them for sale here all the time. If you're going with headers they will be easy to get too.
I would think you will need new mounts.
If your boat does not have a rail kit now would be a good time to put one in. If you can't make your own John @ JM Marine sells them for a pretty good price. He set up HBjet with one and it looks pretty good.
Here's a pic of HB's.
http://free.***boat.net/gallery/Gearhead_Garage/Other_Equipment/DSCN6664.JPG

[Eric]

Going from an Olds to a BBC. You will need:
BBC mounts (or rail kit).
exhaust.
PTO for the drive shaft.
thermostat housing.
water inlet plates.
I think that's everything...
If you decide to go with a 4 pt. mount, I've got a used BBC rear and a new BBC front that I bought a few months back and ended up not using them.
Eric

[Sleek-Jet]

I am definetly leaning twords a rail mount for the engine now that I have seen a few pictures. As a note, the Olds had a 4 point and after I pulled the engine I removed the brackets on the stringers. Half the bolts that went through the stringers were bent!
I probably will fabricate the rail and the engine plates myself, it'll give me something to do (the winters can be long around here.) Thanks for the offer on the 4 point Eric.